Wiki Drug testing-drug classes

[crystal@northgorgiapainclinic.com]

We do in office definitive drug testing and use G0483 for 22 or more drug classes. We are having some issues with one payer stating that we are not testing for 22 or more classes (I think for example they are considering the classes opiates, benzos, etc.). I am trying to locate where in the AMA CPT manual can I find a list of drug classes used for G0480-G0483. Please help.